COMPUTED TOMOGRAPHY SYSTEM AND METHOD FOR TRACKING A BOLUS

• US 20130279783A1
• Filed: 01/04/2012
• Published: 10/24/2013
• Est. Priority Date: 01/06/2011
• Status: Active Grant

• Current Assignee: Koninklijke Philips N.V.
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Schmitt, Holger, Grass, Michael
• Granted Patent: US 9,047,702 B2
• Time in Patent Office: Days
• US Class Current: 382/131
• CPC Class Codes: A61B 6/032 Transmission computed tomography [CT]
• CPC Class Codes: A61B 6/469 for selecting a region of interest [ROI]
• CPC Class Codes: A61B 6/481 involving the use of contrast agents
• CPC Class Codes: A61B 6/488 involving pre-scan acquisition
• CPC Class Codes: A61B 6/504 for diagnosis of blood vessels, e.g. by angiography
• CPC Class Codes: G06T 11/008 Specific post-processing after tomographic reconstruction, e.g. voxelisation, metal artifact correction

Abstract

The present invention relates to a computed tomography system (10) and a corresponding method which enable tracking of a contrast material bolus and which involve a reduced radiation dose. The proposed computed tomography system (10) comprises an acquisition unit including an X-ray source (18) and an X-ray detector (30) for acquiring projection data sets (42, 44, 46), a reconstruction unit (41) for reconstructing a planning image (48) from a first projection data set (42), an identification unit (52) for identifying a region of interest (40) in the planning image (48), a selection unit (54) for selecting a projection angle (60) through the region of interest (40), a calculator (62) for calculating a target projection value (64) for a projection of said region of interest (40) with the selected projection angle (60), a control unit (32) for controlling said acquisition unit to acquire a second, reduced projection data set (44) including projection data from projections of said region of interest (40) with the selected projection angle (60), and a comparator (68) for comparing projection values of the second projection data set (44) with the target projection value (64), wherein the control unit (32) is adapted to control the acquisition unit to initiate the acquisition of a third projection data set (46) based on the comparison result (70) and to reconstruct a diagnostic image (50) from the third projection data set (46).

Claims

1. A computed tomography system comprising:

an acquisition unit including an X-ray source and an X-ray detector for acquiring projection data sets,

a reconstruction unit for reconstructing a planning image from a first projection data set,

an identification unit for identifying a region of interest in the planning image,

a selection unit for selecting a projection angle through the region of interest,

a calculator for calculating a target projection value for a projection of said region of interest with the selected projection angle,

a control unit for controlling said acquisition unit to acquire a second, reduced projection data set including projection data from projections of said region of interest with the selected projection angle, and

a comparator for comparing projection values of the second projection data set with the target projection value,

wherein the control unit is adapted to control the acquisition unit to initiate the acquisition of a third projection data set bused on the comparison result and to reconstruct a diagnostic image from the third projection data set.

2. The system of claim 1, wherein the second, reduced projection data set comprises only projection data from projections of said region of interest with the selected projection angle.

3. The system of claim 1, wherein the identification unit comprises a first user interface, which allows a user to identify the region of interest in the planning image.

4. The system of claim 1, wherein the selection unit comprises a second user interface which allows a user to select the projection angle through the region of interest.

5. The system of claim 4, further comprising a display, wherein the selection unit is adapted for automatically selecting a preferred projection angle and wherein the display is adapted for displaying said preferred projection angle.

6. The system of claim 1, wherein the selection unit is adapted for automatically selecting the projection angle.

7. The system of claim 1, wherein the selection unit is adapted for selecting more than one projection angle and wherein the second reduced projection data set includes projection data from projections of the identified region of interest with the more than one selected projection angles.

8. The system of claim 1, wherein the acquisition unit is adapted to acquire the projection values of the second projection data set at subsequent times and the comparator is adapted for computing a rate of change of the projection values acquired at subsequent times.

9. The system of claim 7, wherein the acquisition unit is adapted to acquire the projection values of the second projection data set at subsequent times with equal time intervals in between.

10. The system of claim 1, wherein the acquisition unit further comprises a dynamic collimator or narrowing the X-ray beam emitted from the X-ray source when the second set projection data set is acquired.

11. The system of claim 1, the acquisition unit is adapted to acquire the second projection data set using a grid-switched X-ray source.

12. A method for tracking a bolus in a computed tomography system comprising:

acquiring a first projection data set and reconstructing a planning image from said first projection data set,

identifying a region of interest in the planning image,

selecting a projection angle through the region of interest,

calculating a target projection value for a projection of the region of interest with the selected projection angle,

acquiring a second, reduced projection data set including projection data from projections of said region of interest,

comparing projection values of the second, reduced projection data set with the target projection value, and

acquiring a third projection data set and reconstructing a diagnostic image from the third projection data set,

wherein acquiring the third projection data set is initiated based on the comparison result.

13. A processor for use in a computed tomography system configured to control the computed tomography system to early out the steps of

acquiring first projection data set and reconstructing a planning image from said first projection data set,

allowing a user to identity a region of interest in the planning image,

allowing a user to select a projection angle through the region of interest,

calculating a target projection value for a projection of the region of interest with the selected projection angle,

acquiring a second, reduced projection data set including projection data from projections of said region of interest,

comparing projection values of the second, reduced projection data set with the target projection value, and

acquiring a third projection data set and reconstructing a diagnostic image from the third projection data set,

wherein acquiring the third projection data set is initiated based on the comparison result.

14. Computer program comprising program code means for causing a computer to control a computed tomography system to perform the following steps when said computer program is carried out on a computer:

acquiring a first projection data set and reconstructing a planning image from said first projection data set,

allowing a user to identify a region of interest in the planning image,

allowing a user to select a projection angle through the region of interest,

calculating a target projection value for a projection of the region of interest with the selected projection angle,

acquiring second, reduced projection data set including projection data from projections of said region of interest,

comparing projection values of the second, reduced projection data set with the target projection value, and

acquiring a third projection data set and reconstructing a diagnostic image from the third projection data set,

wherein acquiring the third projection data set is initiated based on the comparison result.